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Looking at the blurb, it needs a low impedance source, which probably means i couldn't use it after a tube pre.
I would have to connect the DAC output to it, which is ok, except it would then be for CD only and not be a replacement for the pot in the amp.
Perhaps not as useful as i first thought.:scratch:
Hi
Here are the parts that I used for my Lightspeed clone. Please feel free to substitute.
4 x Silonex LDR NSL-32SR3 – We puchased these by mistake...Leo;)...but work fine if you solder a 22R Resistor across the pot
http://uk.farnell.com/silonex/nsl-32...18?Ntt=3692218
The correct LDRs can be found at the following link
http://uk.farnell.com/silonex/nsl-32...in_merch=true&
2 x Bourns 1K Trimmers
http://uk.farnell.com/bourns/3296w-1...78?Ntt=9353178
1 x 100K Pot
http://uk.farnell.com/tyco-electroni...87?Ntt=1173987
2 x RCA Red Sockets
http://uk.farnell.com/neutrik/nys367...29?Ntt=5008529
2 x RCA White Sockets
http://uk.farnell.com/neutrik/nys367...66?Ntt=5008566
You will also require 4x 1/4w 100R resistors and a piece of 60mm x 95mm stripboard. The blue LED is optional ;)
Power Supply
1 x 7805 5v regulator
http://uk.farnell.com/stmicroelectro...0-3/dp/1087086
1 x 10uf Capacitor (All they have in stock)
http://uk.farnell.com/panasonic/eeuf...50v/dp/9692363
2 x 0.1uf Capacitors
http://uk.farnell.com/wima/mks2-0-1u...63v/dp/1006030
Case
http://www.maplin.co.uk/Search.aspx?...mond&source=15
I hope this helps
Nice one!Quote:
Originally Posted by Tripmaster
The NSL-32SR3 was my fault for just quick searching to try and find the order codes, I don't often make too many errors , honest :ner:
Richard, thanks for taking the time and trouble to list all the parts. I am sure I am not the only one who is very grateful. I hope I can build one before Christmas.Quote:
Originally Posted by Tripmaster
Steve
Its the least I could do considering the help I have received in the past :)
It might be worth sourcing an alternative 100k pot as I find its shaft a bit thick (so to speak;))
One thing to consider is that the LSA likes a high impedance (50k+) amplifier on its output; because of this I (and a lot of others) use a Nelson Pass B1 buffer with the volume control replaced by an LSA.
On DIYAudio there is a new version of this buffer coming out soon - I will let you know how that goes with the LSA.
I cannot say I have had any problems on the input side - vinyl / digital - no mismatches.
Someone posted earlier about using a battery - I use SLA'a for both the LSA (2 x 6 volt) and the B1 (3 x 6 volts) - they last at least a week.
All in all this is the best pre-amp I have had in my system.:gig:
pufin: tripmaster mentions a 22r resistor across the pot... is that what will fix mine? (im yet to find the time to get to maplins hence no feedback from me yet)
while i have your atention... the earth fix on the gainclones did nothing.. when i recase them i will post on here for ferther advice i think!
Hi HamishQuote:
Originally Posted by hamish
By soldering 22r resistor across the pot will make the volume control at little less sudden. You can always try a slightly higher value if you find the 22r not to your liking. Give it a go it will only take 5 mins
http://i374.photobucket.com/albums/o...o/P1010909.jpg
at the moment im getting a lot of volume even at zero on the pot? will that fix that?
make it simple guys... rob made it so i dont really know what im doing
Yes it should. Just solder a resistor like in the picture between the red and blue wiresQuote:
Originally Posted by hamish
ta ... thats what rob said, was just checking i understood really
No worries :)Quote:
Originally Posted by hamish
It won't neccessarily fix the "volume at zero" problem. What it will do is give more control over the volume pot range.
I'll second that. You should find the volume control within the medium...to medium high range acceptable.Quote:
Originally Posted by Puffin
Just as a matter of interest has anyone had any light leakage on their LDRs?
I put a lightspeed together on stripboard to see if I liked them and all seemed well until darkness fell. I noticed that one LDR was illuminating the board with a good 8mm ring of light emanating from the led end of the unit. The other 3 just show 2 pinpoints of light around the photocell wires, I assumed I had neglected to cut the strip under the 100r resistor to that one and was shoving too much power through it. The left channel was dropping out and sounded troubled to add to my concerns.
I checked it over the day after and all was well with the build, the supply voltages matched and I was very puzzled to say the least. Running a lens cleaning disc through the playstation sorted the channel loss out and it's done a good few hours since with no issues other than the light leakage. It doesn't seem to be causing any problems, I just wondered if anyone else has seen this.
John
I haven't noticed any leakage, but it has been reported in the past. I guess you could add some sealant to the LDR.Quote:
Originally Posted by john blackburn
Hi Tripmaster
I think I will just ignore it and chuck it into its enclosure. It was in traditional test mode, screwed to a piece of wood. It was just alarming when only one was lit up like a christmas tree. We will see if it gives an early failure but all seems well currently.
The only amp I have tried the lightspeed with is my point to point LM1875 which has a pot and only 22k input. Even with this less than ideal setup I would say there is an improvement in fine detail. It gives a little "niceness" boost if that makes any sense, the music is just "nicer" to listen to.
All told I'm a happy camper and may well pitch in for a matched set in the future, it may get better still.
John
Hi JohnQuote:
Originally Posted by john blackburn
I have put my name down for the next group buy. Rob (Puffin) built his first Lightspeed with the same unmatched LDRs I have. He has just received his matched set so it will be interesting to hear if they are any better. I find the sound through the LS to be a crisper, cleaner sound if slightly lacking a little bass when compared to my previous pre.
I think its definitely a keeper though! :)
I had noticed a slight reduction in bass with my setup too, but everything has tightened up at the same time. I hope that makes sense, I'm no good at this audiospeak.
I'm on with a new LM3875 jobbie that will be taking over from the 1875s on there currently. That will be just a power amp so it will be interesting to see how the sound changes when the 1875s redundant volume pot is removed from the equation.
I'm after a matched LDR set when the project budget has picked up again. There have been 2 amps, a pair of Bib speakers, a phono stage and the lightspeed built this year.
I can happily live with the sound I've got for the time being. If there's more to be got in the future, so much the better.
John
a loss in bass will be gone once you implement the buffers. it's just an impedance mismatch, a usual caveat with the passives. what are the impedances of your source and your power amp?
Hi anubisgrau
If I remember rightly the playstation and amp are both 22k, I don't know about the phonostage without digging out diagrams.
The bass loss is negligible and is more than made up for by the improvement in everything else I am enjoying. I see the Nelson Pass B1 buffer is liked with the lightspeed, that could be an option when the budget recovers.
John
I find I get great bass in fact every night is Paaarrrty night
:gig: :gig: :gig: :gig: :gig: :gig:
I only seem to recall seeing this when I listened to your LightspeedQuote:
Originally Posted by Puffin
http://i374.photobucket.com/albums/o...mouth_bass.jpg
I can only hear the sound of "Carping". Of course I haven't heard yours yet, have I.
Mine sounds Brill!Quote:
Originally Posted by Puffin
http://i374.photobucket.com/albums/o...RILL_photo.jpg
I've just had a brief read up on measuring impedance and now realise the figures I thought to be true are total pollocks, disregard my last post.
The new answer to the question "what are the impedances of your source and your power amp?" is I'm sorry, I don't know.
I will read up on it, I totally misunderstood what the term meant.
John
Anyone using the top device with a Beresford Caiman? If so just wondering if the Caiman line out through the Lightspeed betters the Caiman variable out and inbuilt pre?
If so looks like I will have to give it ago as well.
Regards
Chris
Well I have a lightspeed connected up to my Wolfsoned 7520 and am impressed. Its altered the soundstage in some way so that its become more expansive.
At the moment I am using it with a volume pot in the signal path so the benefit must be limited. Looking forward to trying it witha power amplifier.
Great news Jerry. I am told that my board will be despatched soon. I hope to have everything up and running properly by then.
:)
That's what I found, by quite a large margin. Post some pics when you can.Quote:
Originally Posted by Covenant
When I have replaced the power switch and fitted the knob from a fender!Quote:
Originally Posted by Puffin
Here is a photo of mine sitting on my 7520 on the obligitory Tesco granite slab.
Jerry, that switch with the inbuilt led, I have one the same but green. how did you wire it up? no labels on the terminals on mine!Quote:
Originally Posted by Covenant
Ta
Hi Steve,
Here are the instructions I received from Puffin:
You will need to wire it in after the PS board for DC. +5v from PS board goes to + tag, Middle tag is +5v to potentiometer and the bottom tag Earth is -5v, to be joined to the connection on the main PCB board.)
I managed it ok so anyone can do it!
Cheers Jerry!
it now seems that hifi george has now registred "lightspeed" as a trademark. watch out if you are built a LDR volume control, you can't call it like that anymore unless it's strictily his unit....
I need just a single pair of Silonex LDRs, preferably matched but not essential.
Would anyone out there be willing to sell me some please?
I have a set coming from Uriah, and could tag a few extra on to the order if you wish.Quote:
Originally Posted by jonners
Thanks for that Richard. PM sent.
I like it, a somewhat simpler implementation than the Twisted Pear Joshua Tree and without the scare of EMI bleed from relays.Quote:
Originally Posted by leo
Obviously one could control it from any old motorised potentiometer yes?
//Jan
Hi Jan,
I'd imagine a motorised pot could be added easy enough :) it would make a nice and convenient remote attenuator
I looked at remote motorised pots for mine, but they are 9imo0 too expensive. An excellent idae though.
With the help of Tripmaster in importing a matched pair of LDRs (Thanks Richard :)) I have upgraded my attenuator to the series+shunt version with pleasing results. It does seem to improve on the fixed resistor/shunt LDR version, as others have noted.
I'm using a motorised pot with it for remote control:http://cgi.ebay.co.uk/Remote-Volume-...#ht_3491wt_708
I see that Uriah now has a very good offer going: Board, components and matched LDRs for $30 delivered. You just need to add a 5V power supply and a 100k log pot. http://www.buildanamp.com/LDRs-for-L...RsBOARDKIT.htm
Hello gentleman,
I am sound engineer, and few months ago I've found accidentally info about LDR.
After some research it's definitely a 'must have' for me. I run a little home based mastering studio and I can call myself a talented sound engineer my diy skills regarding electronic are minimal...
I use at my place a tube power amp and passive PMC TB2.
LDR seems to me a perfect solution. I am after transparency in audio signal.
Therefore I am kindly asking users of this forum here, able to build/solder LDR att. (without remote) for me, and I am happy obviously to pay for such job.
Please help!
all the best
Have you looked at http://members.optusnet.com.au/~georgehifi/
Also in the UK Paul Hynes may build one for you (though his is remote controlled): http://www.audiocircle.com/index.php?topic=87969.0
Paul looks in here from time to time.
Quote:
Originally Posted by jonners
Jonners. I have one of those ebay r/c pre-amps. I was not sure how to modify it for use with the L/Speed. I have another r/c Alps pot which I am using at the moment, but would be grateful to know how you did it.
Rob.
Thank you for reply,Quote:
Originally Posted by Clive
I sent an email to George and awaiting for his answer, but for my knowledge he lives in Australia, so shipment could be pricey... Anyway I will try to find out all costs,
The other guy's LDR is with remote which I don't need,
so my offer is still actual for UK based DIY'ers,
come on lads!
all the best
Rob -Quote:
Originally Posted by Puffin
You've already seen this via PM, but in case anyone else wants to know the answer some help can be found here: http://www.diyaudio.com/forums/group...ml#post2168298 (Though I saw this after I had found my own way of doing it, which was slightly different.)